想减缓肌肉衰老，多做高强度运动吧！

The toll that aging takes on a body extends all the way down to the cellular level. But the damage accrued by cells in older muscles is especially severe, because they do not regenerate easily and they become weaker as their mitochondria, which produce energy, diminish in vigor and number.

衰老对身体造成的损害一直延伸到细胞层面。但在衰老的肌肉中，细胞累积的损伤尤为严重，因为它们不易再生。而当细胞内产生能量的线粒体活力和数量减少，这些细胞会更加衰弱。

A study published this month in Cell Metabolism, however, suggests that certain sorts of workouts may undo some of what the years can do to our mitochondria.

《细胞代谢》杂志本月发表的一项研究却表明，某些类型的锻炼或许能消除岁月对我们的线粒体造成的影响。

Exercise is good for people, as everyone knows. But scientists have surprisingly little understanding of its cellular impacts and how those might vary by activity and the age of the exerciser.

众所周知，锻炼对人有益。但关于运动对细胞的影响，以及这些影响因活动和锻炼者的年纪不同会如何变化，科学家的了解出奇地少。

So researchers at the Mayo Clinic in Rochester, Minn., recently conducted an experiment on the cells of 72 healthy but sedentary men and women who were 30 or younger or older than 64. After baseline measures were established for their aerobic fitness, their blood-sugar levels and the gene activity and mitochondrial health in their muscle cells, the volunteers were randomly assigned to a particular exercise regimen.

因此，明尼苏达州罗切斯特梅奥诊所的研究人员近期对72名30岁及以下或64岁以上、身体健康但习惯久坐不动的男性和女性进行了实验。在确立志愿者的有氧体能、血糖指数以及肌肉细胞中基因活性和线粒体健康的基准后，他们会被随机分配到一个特定的锻炼方案。

Some of them did vigorous weight training several times a week; some did brief interval training three times a week on stationary bicycles (pedaling hard for four minutes, resting for three and then repeating that sequence three more times); some rode stationary bikes at a moderate pace for 30 minutes a few times a week and lifted weights lightly on other days. A fourth group, the control, did not exercise.

志愿者中的一部分人每周需进行多次高强度的举重训练；一部分每周需进行三次短时间的健身脚踏车间歇训练（用力蹬车4分钟，休息3分钟，再如此重复3次）；还有一部分人每周以适中的速度蹬车数次，每次30分钟，并在其他时候做低强度举重训练。第四组为对照组，不做运动。

After 12 weeks, the lab tests were repeated. In general, everyone experienced improvements in fitness and an ability to regulate blood sugar.

实验室测验在12周以后再次重复。总的来说，每个人的健康状况和血糖调节能力都有所改善。

There were some unsurprising differences: The gains in muscle mass and strength were greater for those who exercised only with weights, while interval training had the strongest influence on endurance.

有些差别是预料之中的：仅做了举重训练的志愿者在肌肉量和力量方面有更显著的增加，而间歇训练对耐力的作用最大。

But more unexpected results were found in the biopsied muscle cells. Among the younger subjects who went through interval training, the activity levels had changed in 274 genes, compared with 170 genes for those who exercised more moderately and 74 for the weight lifters. Among the older cohort, almost 400 genes were working differently now, compared with 33 for the weight lifters and only 19 for the moderate exercisers.

但在肌肉细胞活检中出现了更多出人意料的结果。在较年轻的试验对象中，进行了间歇训练的志愿者有274个基因出现了活性水平变化，相比之下，运动适中的志愿者出现变化的基因有170个，做举重运动的有74个。在年纪较大的组别内，有将近400个基因现已有活性的改变，相比之下，举重运动者有33个，运动适中者仅有19个。

Many of these affected genes, especially in the cells of the interval trainers, are believed to influence the ability of mitochondria to produce energy for muscle cells; the subjects who did the interval workouts showed increases in the number and health of their mitochondria — an impact that was particularly pronounced among the older cyclists.

大多数受到影响的基因——尤其是进行间歇训练的志愿者细胞中的基因——都被认为影响了线粒体为肌肉细胞制造能量的能力；进行了间歇运动的实验对象表现出了线粒体数量和健康状况的提高——这个影响在年纪较大的脚踏车运动者中尤其显著。

It seems as if the decline in the cellular health of muscles associated with aging was “corrected” with exercise, especially if it was intense, says Dr. Sreekumaran Nair, a professor of medicine and an endocrinologist at the Mayo Clinic and the study’s senior author. In fact, older people’s cells responded in some ways more robustly to intense exercise than the cells of the young did — suggesting, he says, that it is never too late to benefit from exercise.

该项研究的资深作者、梅奥诊所医学教授、内分泌学家斯利库马兰.奈尔博士说，与衰老有关的肌肉细胞健康程度下降似乎可以通过运动来“修正”，尤其是高强度的运动。事实上，年长者的细胞对高强度运动的反应比年轻人的更加强烈——他表示，意思就是，从运动中受益是不存在“太晚”这一说的。